Retail Box, Hot swap Drive assembly to add to or directly replace a failed HP D9419A Hot Swap Drive, except this drive has 15,000 RPM and Extremely Low Power . Only 9 watts, half of the original! This 36.4GB 15,000RPM Low Profile (1") Hot Swap Drive has a 4MB Cache and a Ultra320, Ultra160, Ultra3 and Ultra2 interface compatable with all HP Netservers with low profile hot swap shelves.